High energy clavicle shaft fractures consistently occur at the inflection point: defining morphology and correlation with fracture patterns.

Abstract

<h4>Background</h4>Midshaft clavicle fractures are the most common subtype of clavicle injuries, yet the morphologic basis for their consistent location remains unclear. This study aims to define the anatomical inflection point of the clavicle and investigate its correlation with fracture location, hypothesizing that most high-energy midshaft fractures occur at this morphologically consistent point of curvature transition.<h4>Methods</h4>A retrospective review identified 115 patients with high-energy clavicle fractures confirmed on computed tomography imaging from 2011 to 2023. After applying exclusion criteria, 100 fractures were reconstructed into three-dimensional models. Morphometric analysis was performed using image-modeling software. Polynomial equations were fit to the clavicle centerlines to calculate inflection points using second-derivative analysis. Morphologic variables, including arc lengths, radii of curvature, and fracture distance from the medial border, were measured. Statistical comparisons were made by fracture type (Allman classification), gender, and morphometric parameters using analysis of variance, <i>t</i>-tests, and nonparametric tests.<h4>Results</h4>Of the 115 analyzed clavicles, 78% were midshaft fractures. Fractures consistently occurred at approximately 60% of the clavicle's total length from the medial border, corresponding to the inflection point of curvature. Medial arcs averaged longer lengths and larger radii of curvature than lateral arcs. Gender analysis revealed shorter clavicle lengths and differing arc ratios in female patients (<i>P</i> < .05). No significant difference in fracture location was observed by gender or laterality.<h4>Conclusion</h4>High-energy clavicle fractures consistently occur at the anatomical inflection point, a morphometrically distinct region where curvature transitions from medial to lateral. Recognition of this consistent fracture location may improve surgical planning, implant design, and biomechanical modeling.